1. Field of the Invention
The present invention relates to a differential assembly, and more particularly to a pinion shaft for the differential assembly for motor vehicles, having an H-shaped cross-section.
2. Description of the Prior Art
Conventionally, differential assemblies well known in the prior art, are arranged in a power transmission system of a motor vehicle to allow a pair of output shafts operatively coupled to an input shaft to rotate at different speeds, thereby allowing the wheel associated with each output shaft to maintain traction with the road while the vehicle is turning. Such a device essentially distributes the torque provided by the input shaft between the output shafts.
Essential part of the differential assembly is a pinion shaft rotatably supporting differential pinion mate gears in mesh with side gears that are, in turn, drivingly coupled to the output shafts of the motor vehicle. Usually, the pinion shafts of the differential assemblies are cylindrically shaped and have a circular cross-section. Some pinion shafts, known in the prior art, have flattened portions for improving lubrication.
The present invention provides a novel arrangement of a pinion shaft of a differential assembly for motor vehicles.
In accordance with the present invention, at least a section of the differential pinion shaft that supports a pinion mate gear member, has a substantially H-shaped cross-section with added oiling radii.
In accordance with the first embodiment of the present invention, an entire length of the pinion shaft has a substantially H-shaped (or I-shaped) cross-section having a substantially uniform size in a lengthwise direction thereof.
In accordance with the second embodiment of the present invention, the pinion shaft has opposite end sections and a central section. The entire length of the pinion shaft has a substantially H-shaped cross-section, wherein said H-shaped cross-section of said end sections has substantially uniform size across an entire length thereof and said H-shaped cross-section of said central section has a substantially varied size across an entire length thereof.
In accordance with the third embodiment of the present invention, the pinion shaft has opposite end sections adapted to engage a differential case and a central section rotatably supporting the pinion mate gears, wherein the end sections are substantially cylindrical, while the central section has essentially H-shaped cross-section having a substantially uniform size across an entire length thereof.
In accordance with the third embodiment of the present invention, the pinion shaft has opposite end sections adapted to engage the differential case and the central section rotatably supporting the pinion mate gears, wherein the end sections are substantially cylindrical, while the central section has essentially H-shaped cross-section having a substantially constant area in a lengthwise direction thereof.
In accordance with the forth embodiment of the present invention, the pinion shaft has opposite end sections adapted to engage the differential case and the central section rotatably supporting the pinion mate gears, wherein the end sections are substantially cylindrical, while the central section has essentially H-shaped cross-section. The central section, in turn, has a pair of opposite gear bearing segments interconnected by a link segment. The H-shaped cross-section of the gear bearing segments has a substantially uniform size across an entire length thereof and the H-shaped cross-section of the link segment has a substantially varied size across an entire length thereof. The differential pinion shaft in accordance with the present invention represents an improvement over the prior art that substantially reduces weight of the differential pinion shaft, increases a strength-to-weight ratio, and improves lubrication.